Many Australians live in regions affected by tropical cyclones and it’s important they have access to the latest information and warnings about these dangerous severe weather events.
During the cyclone season, 1 November to 30 April, the Bureau of Meteorology keeps a 24-hour watch on developing tropical weather systems. We keep the public informed through weather forecasts and warnings issued via our website and the media.
The Bureau is responsible for the issue of all warnings and related advices and information for tropical cyclones affecting the Australian area of responsibility (See Figure 1). This includes the coastal waters and land areas of Australia including Christmas Island, Cocos Island, Lord Howe Island and Norfolk Island.
Around the world a network of Regional Specialised Meteorological Centres (RSMCs) and Tropical Cyclone Warning Centres provide global coverage for tropical cyclone warnings (see Figure 2).
To learn more about tropical cyclones around the world, visit the World Meteorological Organization's Severe Weather Information Centre.
The Bureau of Meteorology produces tropical cyclone warnings as well as related information about tropical cyclones and the tropical cyclone season. These products include Tropical Cyclone Advices and Forecast Track Maps, as well as seasonal outlooks and information bulletins.
Keep up to date with the latest warnings on the Bureau's website, app and Twitter feed. Current tropical cyclone information is also available by telephone on 1300 659 210 (around 27.5c incl. GST. More from international, satellite, mobile or public phones)
Tropical Cyclone Advices are issued whenever a tropical cyclone is likely to cause winds in excess of 62 km/h (gale force) over Australian communities within the next 48 hours. The Tropical Cyclone Advice lets people know when they might be affected by issuing either a Watch or Warning for each community in the path of the cyclone.
While the threat remains, a Tropical Cyclone Advice will be issued every six hours, increasing to every three hours when cyclone warnings are required. In some circumstances, when a cyclone approaching the coast is under radar surveillance, the advices may be issued hourly.
When a cyclone forms, or is expected to form, we produce a Tropical Cyclone Forecast Track Map. This shows important information about the cyclone's intensity, movements, and the Watch and/or Warning zones, to help you make the best decisions for you and your family before, during, and after the cyclone. The Forecast Track Map is issued at the same time as the Tropical Cyclone Advice and contains all the information included in the Advice. Unlike Tropical Cyclone Advices, it is issued for all tropical cyclones, even if there is no threat to Australian communities.
The first step in reading the track map is to look for your location on the map to check if you are in a Watch or Warning area. Check where the tropical cyclone is in relation to your location and the forecast path of the cyclone. Note that you can still be at risk even if you are not within the range of likely tracks.
The Warning area is where gale force or stronger winds are expected to occur within the next 24 hours. This is shown by darker orange shading on the map. The lighter orange shading shows the Watch area, where gale force or stronger winds might occur within the next 24 to 48 hours.
The next step in reading the track map is to follow the track, shown by the black line and arrows. These indicate where the cyclone has been and its current location and intensity (highlighted in blue text). The number in the centre of the cyclone symbol at each time stamp is the intensity category of the cyclone. The higher the number, the stronger the intensity, with category 5 being the strongest. Coloured circles show the radius of the very destructive core, the radius of destructive winds and the size of the gale force winds.
Watch our video about Tropical Cyclone Forecast Track Maps
The Bureau issues an Australian Tropical Cyclone Seasonal Outlook in October. It provides a prediction of the level of tropical cyclone activity expected over summer.
Tropical Cyclone Seasonal Outlooks are also produced in Western Australia, Northern Territory and Queensland.
The Tropical Cyclone Outlook is issued daily during the tropical cyclone season for the Northern and Eastern Australia and all year in the Western Region.
Each Tropical Cyclone Outlook has the following information:
A statement that no cyclones are expected to develop in the next three days.
A brief explanation of the weather situation and the probability of tropical cyclone development on each of the following three days. The Tropical Cyclone Outlook may also contain statements about the probability of a tropical cyclone forming within the next week (over the next seven days rather than just the next three days) when there are clear signs of an increase in risk over that period.
The Tropical Cyclone Outlook may be updated if there is a significant change in the forecast.
Tropical Cyclone Information Bulletins are issued when a tropical cyclone (or developing tropical low) is active in the Australian area of responsibility, but it is not expected to cause winds in excess of 62 km/h (gales) in Australian communities within the next 48 hours. Whenever an Information Bulletin is issued a Tropical Cyclone Forecast Track Map will also be issued.
The Tropical Cyclone Technical Bulletin is a formatted text product that provides technical details about the cyclone. It is issued once every 6 hours during the life of the cyclone. The Technical Bulletin is used to communicate technical information to our partners and high-end users. This product may contain data and comments of a scientific nature that would not be expected to be understood by a general audience. It should not be relied on for guidance by those affected by the cyclone.
To facilitate easy exchange of information, there is a standard format to represent analysed and forecast data for tropical and extra-tropical cyclones. This format, called Cyclone XML (CXML), is descriptive and human-legible, making it easy for all human users and most automated applications to read. CXML is defined so it can carry data from observations and analyses, manual and NWP forecasts, multiple cyclones and multiple forecasts (ensembles).
Find out more http://www.bom.gov.au/cyclone/cxmlinfo/
The Bureau of Meteorology publishes a Tropical Cyclone Service Level Specification that describes the publicly available tropical cyclone services we provide and when each product is issued. The SLS is available here.